U.S. Pat. No. 7,604,601 B2 discloses a medical imaging system for imaging a patient's body. The medical imaging system includes a catheter having a position sensor and an ultrasound imaging sensor, wherein the position sensor emits electrical signals indicative of positional information of a portion of the catheter in the patient's body, and the ultrasound imaging sensor emits ultrasound energy to a target in the patient's body, receives ultrasound echoes reflected from the target in the patient's body and emits signals relating to the ultrasound echoes reflected from the target in the patient's body. A position processor is operatively connected to the catheter for determining positional information of the portion of the catheter based on the electrical signals emitted by the position sensor. The system further includes a display and an image processor operatively connected to the catheter, the position processor and the display. The image processor displays on the display a catheter icon in a same orientation as an orientation of the portion of the catheter in the patient's body based on the positional information derived from the position sensor. The image processor also generates an ultrasound image of the target based on the signals emitted by the ultrasound sensor and depicts in real-time the generated ultrasound image on the display in the same orientation as the orientation of the portion of the catheter in the patient's body. The positional information of the portion of the catheter, which is based on the electrical signals emitted by the position sensor, can have a relatively low accuracy, which may lead to an inaccurate positioning of the catheter within the patient's body.